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nfsd4: remove state lock from nfs4_state_shutdown

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Protection of __nfs4_state_shutdown() with nfs4_lock_state() looks redundant.

This function is called by the last NFSd thread on it's exit and state lock
protects actually two functions (del_recall_lru is protected by recall_lock):
1) nfsd4_client_tracking_exit
2) __nfs4_state_shutdown_net

"nfsd4_client_tracking_exit" doesn't require state lock protection, because it's
state can be modified only by tracker callbacks.
Here a re they:
1) create: is called only from nfsd4_proc_compound.
2) remove: is called from either nfsd4_proc_compound or nfs4_laundromat.
3) check: is called only from nfsd4_proc_compound.
4) grace_done; called only from nfs4_laundromat.

nfsd4_proc_compound is called onll by NFSd kthread, which is exiting right
now.
nfs4_laundromat is called by laundry_wq. But laundromat_work was canceled
already.

"__nfs4_state_shutdown_net" also doesn't require state lock protection,
because all NFSd kthreads are dead, and no race can happen with NFSd start,
because "nfsd_up" flag is still set.
Moreover, all Nfsd shutdown is protected with global nfsd_mutex.

Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
This commit is contained in:
Stanislav Kinsbursky 2012-11-21 18:07:38 +03:00 committed by J. Bruce Fields
parent dba88ba55a
commit ec28e02ca5
1 changed files with 0 additions and 2 deletions
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2
fs/nfsd/nfs4state.c
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@ -4930,9 +4930,7 @@ nfs4_state_shutdown(void)
cancel_delayed_work_sync(&nn->laundromat_work);
destroy_workqueue(laundry_wq);
locks_end_grace(&nn->nfsd4_manager);
nfs4_lock_state();
__nfs4_state_shutdown(net);
nfs4_unlock_state();
nfsd4_destroy_callback_queue();
}